Electric ground connector plug



G U L P. R m R Em m O C am Kw e I R T C E L B May 16, 1961 Filed April 2, 1959 FIG. 2

FIG. 3

INVENTOR.

WERNER K. BENDER ATTORNEYS United States Patent ELECTRIC GROUND CONNECTOR PLUG Werner K. Bender, Hultenius St., Plainville, Conn.

Filed Apr. 2, 1959, Ser. No. 803,636

Claims. (Cl. 339-14) The present invention relates to electric connector plugs adapted to coact with an outlet or receptacle having female contact elements, and more particularly to electric connector plugs having a grounding contact or pm.

In many installations it is required, or at least desirable that appliances and other apparatus are connected to ground, and for this purpose the plug on the connecting cord leading to the appliance or other apparatus has three contact elements or blades, one of which constitutes the grounding contact. However, in many instances, the available receptacles or wall outlets have two female contact elements only.

Various designs of adaptors are known which can be interposed between the cord and plug and the receptacle or outlet, but the use of such adaptors is inconvenient.

There are also known plugs which can be converted from a plug with three male contact elements into a plug with two male contact elements only and vice versa. However, designs of this kind as heretofore known, are unreliable and inconvenient as they require loosening or tightening of components by the user, often entailing the use of special tools not always readily available.

It is an object of the present invention to provide a novel and improved convertible connector plug of the general kind above referred to, which can be readily and rapidly converted into two-element or threeelement plug, is electrically and mechanically satisfactory, and can be inexpensively manufactured.

Another object of the invention is to provide a novel and improved connector plug which can be converted either into a two-element or three-element plug without assembly or disassembly of current carrying components and without requiring special skill or tools.

Still another object of the invention is to provide a novel and improved connector plug of the general kind above referred to, the grounding element of which is pivoted into either an operative or inoperative position and is self-retaining in either position, placement of the grounding element into an operative position permitting insertion of the plug in the outlet or the receptacle without the use of an adaptor.

It is also an object of the invention to provide a connector plug, the pivotal grounding element of which can be conveniently locked in its erected or operative position thereby assuring satisfactory mechanical and electrical properties of the plug.

It is a further object of the invention to provide a connector plug which has connected to its pivotal grounding element a flexible lead such as a pigtail. This lead carries at its free end a contact and locking element and when the plug is applied to a three-pole receptacle the element can be used as a locking element for securing the pivotal grounding element in its operational position and when the plug is applied to a two-pole receptacle the element can be used as a contact element to connect the grounding element of the plug to ground.

'4 by dotted lines.

Other and further objects, features and advantages of the invention will be pointed out hereinafter and set forth in the appended claims constituting part of the application.

In the accompanying drawing a preferred embodiment of the invention is shown by way of illustration and not by way of limitation.

In the drawing:

Fig. 1 is a perspective fragmentary view, partly in section, of a connector plug according to the invention.

Fig. 2 is an elevational section of a connector plug according to the invention.

Fig. 3 is a simplified section taken on line 33 of Fig. 2 showing the grounding element in its erected or operative position.

Fig. 4 shows the grounding element of Fig. 3 in its inoperative position.

Fig. 5 shows the plug of the invention ready for insertion into a receptacle having a female grounding element, and

Fig. 6 is a view similar to Fig. 5, but showing the plug ready for insertion into a receptacle having two female contact elements only.

Referring now to the figures in detail, the connector plug comprises a shell 10 made of suitable insulation material. The shell has at least one fiat side 10a from which protrude two contact elements shown as blades 11 and 12 fixedly mounted within the body of the shell. The inner end of each blade terminates in a wire terminal 13 to which the wires of the connecting cord 14 are connected as is shown in Fig. 2.

The connector comprises as grounding contact a round grounding pin 15, although a flat grounding contact may, of course, also be used. Pin 15 is mounted in the shell body by means of a contact sleeve 16 which in turn is fitted in a suitable opening 17 formed within the shell body. The inner end of the sleeve constitutes a Wire terminal 18 to which the grounding or third wire of cord 14 is connected by means of a binding screw 19. Part of the sleeve is longitudinally slotted, two diametrically opposite slots 20 being provided. These slots impart to the sleeve a certain springiness as is indicated in Fig. The slots also serve as a holder for pin 15 and are for this purpose widened at 20a. As may be noted, the widened portions 20a define part of a circular outline. A pivot pin 21 extends across the sleeve and more specifically through the portion thereof including the widened slot sections 20a. Slotted sleeve 16 in conjunction with pin 21 form yieldabl-e hinge means for grounding pin 15 which permit placement of the pin either in the up position of Fig. 3 or in the down position of Fig. 4. In the position of Fig. 3 which is also shown in Figs. 1, 2, 5 and 6, the pin is erected and parallel to fixed contact blades 11 and 12 and this constitutes the operative position of the grounding pin. In the position of Fig. 4, indicated in dotted lines in Figs. 1 and 2 also, the pin occupies a position transversely of blades 11 and 12 and this position of the pin constitutes the inoperative position thereof.

As is evident and indicated in Fig. 4, the springiness of the slotted sleeve portion will yieldably retain the grounding pin in either position. More specifically, in the operative position pin 15 will extend into the sleeve in alignment therewith whereas in the inoperative position pin 15 will be cradled and held with a. frictional grip between the two branches of the sleeve formed by the slots.

In order to permit the plug to be pushed fully home into its receptacle or wall outlet when grounding pin 15 is in its inoperative position, a groove 25 is provided in the flat side 10a of the shell. This groove accommodates the grounding pin in its inoperative position as is indicated in Figs. 1, 2 and 6 in dotted lines.

Fig. 5 illustrates the insertion of the plug with its grounding pin in operative position, into a receptacle or wall outlet having the appropriate female contact elements to receive blades 11 and 12 and grounding pin 15. The receptacle or wall outlet should be visualized as being of conventional design.

When it is desired to insert the plug in a receptacle or wall outlet of the kind shown in Fig. 6 which has female contact elements for blades 11 and 12 only, grounding pin 15 is pivoted into its groove 25 and the plug can then be inserted in a conventional manner.

As is apparent, to convert the plug for use either with a receptacle of the kind shown in Fig. 5 or with a receptacle of the kind shown in Fig. 6, all that is necessary is to pivot grounding pin 15 either into one or the other of its two positions and it will remain in the selected position by the springy grip of sleeve 16.

The invention further provides means for locking pin 15 in its operative position and for establishing ground connection when the plug is applied to the two-pole receptacle of Fig. 6. For this purpose, a flexible insulated wire 27 such as a pigtail is connected to the inner terminal of pin 15 by means of binding screw 19 as can best be seen in Fig. l. The pigtail carries at its free end, electrically connected to it,'a screw 28 which serves as a locking and contact element. This screw may be threaded into a bore 29 of pin 15 when the pin is in its erected or operative position thereby locking the pin in said position, or it may be threaded into the receptacle bore provided for the usual mounting screw for the receptacle as is shown in Fig. 6. The pigtail when not used or when screw 28 is inserted into bore 2 9, is accommodated in a peripheral groove formed in the outside walls of shell 10. The length of wire 717 is preferably such that screw 28 just reaches bore 29 when the wire is wrapped about groove 10' as is shown in Fig. 5.

While the invention has been described in detail with respect to a certain now preferred example and embodiment of the invention it will be understood by those skilled in the art after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended, therefore, to cover all such changes and modifications in the appended claims.

What is claimed as new and desired to be secured by Letters Patent is:

l. A convertible electric connector plug with grounding contact, said plug comprising an insulation shell, two male contact elements fixedly mounted in said shell protruding therefrom, a third male contact element, and yieldable hinge means supporting said third contact element in the shell pivotal between an operative position parallel to the two fixed contact elements and an inoperative position substantially transversely thereto, said hinge means including a metal sleeve mounted within said shell parallel to said two fixed contact elements, the inner end of said sleeve constituting a wire terminal and the outer end having two longitudinal, diametrically opposite slots to impart springiness to said slotted sleeve, and a hinge pin for said third contact element crossing said sleeve at a right angle to said slots, said slots being partly widened to receive said third contact element with a pressure grip in its inoperative position, said third contact element occupying a position in alignment with the sleeve in the operative position of said third element, said third contact element constituting the grounding contact.

2. A convertible electric plug with a grounding contact, said plug comprising an insulation shell having a flat side, two male contact elements fixedly mounted within said shell protruding from the flat side thereof, a third male contact element constituting the grounding contact, a springy hinge means pivotally mounting said third contact element for selective movement of the third contact element into an operative position parallel to said fixed contact elements and an inoperative position transverse of said fixed contact elements, said hinge means including a metal sleeve mounted within said shell parallel to said two fixed contact elements, the inner end of said sleeve constituting a wire terminal and the outer end having two longitudinal, diametrically opposite slots to impart springiness to said slotted sleeve, and a hinge pin for said third contact element crossing said sleeve at a right angle to said slots, said slots being partly widened to receive said third contact element with a pressure grip in its inoperative position, said third contact element occupying a position in alignment with the sleeve in the operative position of said third element,

said flat shell side including a groove for receiving therein the third contact element in its inoperative position, and releasable locking means for positively locking said third contact element in its operative position.

3. A convertible electric connector plug with grounding contact, said plug comprising an insulation shell having a flat side, two male contact elements fixedly mounted in said shell protruding from the fiat side thereof, a third male contact element, hinge means supporting said third contact element in the shell pivotal between an operative position parallel to said two fixed contact elements and an inoperative position substantially transversely thereto, said third contact element constituting the grounding contact, and said flat side of the shell including a straight groove for receiving therein the grounding element in the inoperative position thereof, a flexible insulated wire conductor connected on one end to said third contact element and protruding from the shell, and a locking and contact element electrically connected to the free end of said wire, said third contact element having a bore for receiving said element in the operative position of the third contact element to lock the latter in said position, said locking and contact element also being adapted to be inserted into a mounting bore of a receptacle for the plug to establish a ground connection.

4. A plug according to claim 3 wherein said shell has in its outer walls a peripheral groove for accommodating said wire by wrapping it about the shell.

5. A plug according to claim 4 wherein the length of said wire is such that when it is accommodated in said groove, the element connected to its free end just reaches said bore in the third contact element.

References Cited in the file of this patent UNITED STATES PATENTS 1,506,184 Kellner Aug. 26, 1924 2,024,814 Bell Dec. 17, 1935 FOREIGN PATENTS 326,324 Switzerland Apr. 15, 1958 

